LEDs are among the most commonly used components in electronic projects – from simple circuits to complex systems. However, for an LED to function properly and safely, it requires an appropriate resistor to limit the current flow. In this article, we will show you how to easily select the right resistor for an LED and illustrate this with an example.
Why Do You Need a Resistor?
LEDs are very sensitive to excessive current. Exceeding the allowable current can damage them, which is why adding a resistor is crucial. The resistor limits the current flowing through the diode, protecting it from damage.
How to Calculate the Resistor Value?
To select the appropriate resistor, we need to use a simple formula based on Ohm's law:
Where:
R is the resistance we want to calculate (in Ohms),
Vpower is the supply voltage provided to the circuit,
VLED is the operating voltage of the LED (voltage drop),
ILED is the current of the LED (usually given in mA).
Example
Let's assume we have an LED with a voltage drop of 2V and a maximum current of 20 mA (0.02 A). We want to power it with a 9V battery. To select the appropriate resistor, we substitute these values into the formula:
We obtain a resistor value of 350 Ω. In practice, it is best to choose the nearest standard value, which is 360 Ω.
Summary
Choosing the right resistor for an LED is crucial to ensure its proper functioning and long lifespan. Remember that calculating the resistor value is simple, and you can do it using a formula based on Ohm's law. Take care of your LEDs and always select the appropriate resistor!
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